SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ffc629a66b3c8da1aa35181c06615b9bf34b19dd0dd94c0dfb1addac0d586c1' 
  AND token = 'bOjTIgCmZonhnWYytWmm7ehwO5jwpG9L6Pllj7heXoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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