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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '02ab55a886e405df4357f3e360e9fa1759d93daf69c11c23e330b2cb10a8f0f2' 
  AND token = '4fCxlhbcbHoXO58POtDJviygfn9+2hCQ25FduV8sDSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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