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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd3fafd8a0e899c604e64c99c93912332399f0477e7821e7282713fda1e14db83' 
  AND token = 'c2vTPkrCE1Ok0oYkrzhZvLWgwUb5afMrM/2F3Ijt0UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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