SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da2ea4a42a0aaf13787424a0cd85c9092728271ee76e1ed721d4eadaec0b4e34' 
  AND token = 'ck7TseIAE/fsCN4poJRs86tLB6mDr9ve3hxVzbUoZuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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