SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fdbb3e42ec4a9af3920cb9eeb1139a28824de17830764c166fdd40175d3494b' 
  AND token = 'Effgq+WmbXFiYsQTU3BoCpMJwfAZ9nPsomG7Q/Zqn7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}