SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b1a7c5c83d9db6b3a4a8474b0c9e4a4c59bf7cb2f38282597f289f2dfe107fd' 
  AND token = 'f1KpEtURqVXWKqYGKTT2wn4Miw/lTBvnoqvfRQ2Tz58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}