SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e559800a2c3c021b5ca2f7b77da33d351109a4faf4fdccf82cbe14ce30e73bdb' 
  AND token = 'p5XEqX238O2W35oV8HmONdsV0LagOU2GrzzNdetSCNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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