SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8aaa55c801937d9680d782711c2e3237c4621ebb9c24549e30ca749e0e7bc1a' 
  AND token = 'iVKUuHycFhXNpYf+mnNMn+1o4CIWBN1Omz0sAWkrCg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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