SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd390f3f49e507172fcbec2ac401b9241d3210a907f4bdbc655f448f750d76bdd' 
  AND token = 'DfCR6ogNS4z9gVABbIcG5DeI6RgNvqkYFtpT4ycAOSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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