SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e747067d9c68775776e7215fd173da58a298fac17b849c20d2682b87194f5fe5' 
  AND token = 'KPPlAoZ15vy2vUbn3+wG/f+YYevQxuB+czbxuRXbw6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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