SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd5f16d9d06c4021b1f2f52706cac189c2bad8749c5a46aea174e5a6fe05d3a3' 
  AND token = 'cLSbBP0w/h8vrmUD+Q3D/8FvZuSt9lDLdt+KTGY7UtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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