SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bea40ccdd7593623f76a1701c8641240f462c4539b8a5da74fff65600a28a2cb' 
  AND token = 'sM6RtgfiY/55ueU0deSnlujpAbLMCL705+x3Gt6OL2M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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