SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3083970e560e557d5dd092abfd9ac3d96bc583715465a14c52e23e7333317df0' 
  AND token = 'wmIi1/OXff4immJ1PBCGYMRBtFXp18aqHZqmVADr+cc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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