SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da23d5ae1b2cae73885834a77b6d970bdadee82e92518290d0494a8409bb9a1d' 
  AND token = 'OCrKlEeucWSzCeB3JGEc3VlA/UYCenoO+G+/LDD0gBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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