SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea8696ec6749725810bdb386f78317e0ffa412f77ec78fda7ec5613a5fc209ff' 
  AND token = 'z3psjR59uArTRhsU4rQgvGndNwSiGEAD3AkR0PK8APo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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