SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510d15fcb18a6b152a1a3681451bd4af8563d757b2f5303aa3296cdfe67d2ab7' 
  AND token = '0Foi1NEQ2sCQDUjfiz55lLDMqumGSyvV36Mkg+JzLK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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