SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb49346bb3f4e0fbb932bfcd2192e8fd68738da6e7ff2add76ad985f08371c51' 
  AND token = 'xzH+xKkCItKIPSXO6dfr2FElQVFy5ZkSDe7OPJPrj98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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