SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1dc4a8e3e418de84716b05c2c8363853d2224431f133bc8de2855ea4fe023a1' 
  AND token = '6ZmRwq8D8AFclzKYSz72TeY0Qcgos6p1bEhOIoCoxmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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